Polycrystalline samples of AlxFe2-xZnO4 ferrite, where x was equal to 0, 0.3, 0.6, 0.9 or 1.2, were studied. A decrease in the density with Al concentration was attributed to the substitution of Fe3+ for Al3+, which had a smaller atomic radius and lower atomic weight than Fe3+. An increase in the Al concentration led to a decrease in the diffusivity of vacancies.

A.Tawfik: Phase Transitions, 1995, A54[4], 203-9